Taken from the Rural Enterprise Solutions Knowledge Network Weekly Summary
Biochar is a fine-grained, highly porous material similar to charcoal, that is produced from the decomposition of plant-derived organic matter (biomass) in a low- or zero-oxygen environment (a process known as pyrolysis). Biochar is already found in soils around the world as a consequence of naturally-occurring fires and, in the Amazon, as a deliberate result of its addition by past human populations (the so-called terra preta soils). These terra preta soils are famous for enhancing the year-on-year fertility of soils and are, nowadays, highly valued as composts.
Contemporary interest in biochar is, first and foremost, driven by its potential role as a response to the problem of climate change. This is through the long-term storage of carbon in soils in a stable form. If untreated (i.e. non-pyrolysed) organic matter is added to soils, many of the nutrients contained therein are released. The carbon in the material is rapidly converted into carbon dioxide (‘mineralised’) and released to the atmosphere. Usually, all the carbon has disappeared as CO2 within 1 to 5 years, which is why adding organic matter to soils doesn’t help very much in efforts to limit climate change. By contrast, the carbon atoms in biochar molecules are strongly bound to one another, and this makes biochar resistant to attack and decomposition by micro-organisms.
The full report can be downloaded from the Defra website.
In my view, this means that biochar could be useful stuff. The next question is can it be produced as a product of heather burning?